1. Field
The following generally relates to Fibre Channel networks and devices, and more particularly, to trunking with port aggregation for fabric ports in a Fibre Channel fabric and attached devices.
2. Related Art
In recent years, the capacity of storage devices has not increased as fast as the demand for storage. Thus, a given server or other host must access multiple, physically distinct storage nodes (e.g., disc drives or disk drive systems). The Storage Area Network (SAN) was developed to solve storage limitations. Generally, a SAN is a high-speed, special-purpose network that interconnects different data storage devices and associated data hosts on behalf of a larger network of users. A SAN may use various types of network traffic, but typically a SAN employs Fibre Channel (FC) frames.
Traditionally, designers of SANs built separate fabrics, referred to as “SAN islands”. For example, a business might employ one SAN island for human resource applications, another SAN island for engineering applications, another for marketing, etc. Each SAN island contains a physically isolated switch or group of switches for connecting hosts to storage devices. While this approach may enforce separation and data between various groups in an organization, hardware and management resources are frequently under-utilized.
More recently, some switches, such as the MDS9000 family of switches commercially available from Cisco Systems, Inc. of San Jose, Calif., have provided the capability to deploy virtual SANs (“VSANs”). With this approach, multiple SAN islands may be collapsed to a single physical infrastructure, thereby reducing hardware costs and improving manageability, while maintaining the stability and traffic isolation of the SAN island model. Each VSAN is logically separate and may be assigned to a separate group, e.g., marketing, engineering, etc. In this collapsed fabric model, some or all switches and inter-switch links in the fabric carry traffic for multiple VSANs. Implementation of virtual fabrics is known as “VSAN trunking” or generally “trunking”. VSAN trunking allows traffic in multiple VSANs to be transmitted over a single physical link.
Furthermore, neighboring devices in a FC network may be connected through multiple physical links. For example, a host (e.g., a server, storage device, etc.) may be connected to ports on the fabric (“fabric ports”) using a plurality of physical links. Conventionally, the protocols are designed such that each link between a host and FC fabric operates independently. Two or more connections to the fabric potentially offer a host much higher total available bandwidth and fault tolerance against link failures (known as “link aggregation”). However, since the links are treated independently, a host must implement complex logic to split the input/output (IO) operations between all available links. Further, the host must implement additional logic to handle the failover between links in the case of link failures. Further, there are no known techniques for implementing the combination of trunking and link aggregation between a host and an FC fabric to which it is attached.
Accordingly, there exists a need in the art for a method and apparatus that provides trunking with port aggregation for fabric ports in a Fibre Channel fabric and attached devices.